Solutions to Common Aluminum Die Casting Defects: Porosity / Cracks / Deformation? 5 Key Process Control Points

Solutions to Common Aluminum Die Casting Defects: Porosity / Cracks / Deformation? 5 Key Process Control Points

Aluminum die casting is widely used in automotive, electronics, home appliance and other industries due to its advantages of high-efficiency forming and lightweight. However, defects such as porosity, cracks and deformation occur frequently during the production process, which seriously affect product quality and qualification rate. In fact, these problems can be effectively avoided by accurately grasping 5 core process control points. This article will detail the operation points of each control point to help enterprises improve the quality of aluminum die casting products.

First, control of aluminum melt smelting and purification. Residual gases and impurities in the aluminum melt are the main causes of porosity. It is necessary to adopt vacuum smelting or online degassing processes, combined with refining agents to remove impurities. At the same time, control the smelting temperature at 700-720℃ to avoid increased gas solubility caused by excessive temperature, thereby reducing defect risks from the source.

Second, control of mold temperature and coating. Uneven mold temperature is likely to cause cracks and deformation. It is necessary to preset the mold temperature according to the product structure: 180-220℃ for thin-walled parts and 120-160℃ for thick-walled parts. At the same time, apply a uniform high-temperature resistant release agent to reduce the frictional resistance between the aluminum melt and the mold, and avoid cracks caused by local stress concentration.

Third, optimization of die casting parameters. Unreasonable injection speed and pressure will lead to uneven filling of the aluminum melt, resulting in porosity or cold shuts. It is necessary to adjust the injection speed according to the product thickness: high-speed and high-pressure filling for thin-walled parts, and appropriately reduced speed for thick-walled parts. At the same time, control the holding pressure and time to ensure full solidification of the aluminum melt and reduce shrinkage deformation.

Fourth, design of gating system and exhaust. An unreasonable gating system will cause vortex and gas entrainment of the aluminum melt. It is necessary to optimize the runner structure to ensure smooth filling of the aluminum melt. Set sufficient exhaust grooves at the end of the cavity and dead corners to timely discharge gases and coating volatiles in the cavity, avoiding porosity.

Fifth, standardization of post-processing processes. If the die-cast product cools too quickly or the heat treatment parameters are improper, residual stress is likely to occur, leading to cracks. It is necessary to adopt a stepped cooling method to avoid excessive temperature difference. During heat treatment, accurately control the heating, holding and cooling rates to effectively release stress and ensure product dimensional stability.